The study examines the efficacy and safety of Analgecine in the treatment of chronic pain in
patients with low back pain for 3 months after surgical treatment. It is a randomized,
placebo-controlled, double blind, multi-center phase III clinical trial. Patients with
chronic low back pain for 3 months after surgical treatment is recruited (age between 18 and
70; pain visual analysis scale (VAS) between 3 and 8). After randomization, subjects are
divided into 3 groups: 1) Treatment with Analgecine (Experiment group); 2) Treatment with
Neurotropin (positive control group); 3) Placebo group. Subjects will be undergone 4
measurement time points on day 0, 7, 14, and 21. In each time points, subjects are required
to score their pain with pain VAS and to have regular blood, urine, and renal/liver function
tests. The changes of the pain VAS at day 21 are compared between groups.